Recording of a radio station format change for 96.3 KTWN-FM/Minneapolis. Contains last 16 hours of weird robot voice stunt format (formerly K-TWIN), and first 4.5 hours of new Alternative format (Go 96.3). Format change is at 3pm on January 5, 2015 (2015-01-05-1500).
Recorded by Ron Gerber in mono from air onto hard drive, using Technics ST-S78 tuner and ART USB Phono Plus, leaving 2-3 dB of headroom for stunt format files and about 1 dB of headroom for new format files, and no further processing. In the spectrograms, you can clearly see the 19 kHz pilot tone from the FM encoding.
There's also a rip of the radio station's 48 kbps 22 kHz stereo mp3 stream, including the last 46 hours of the stunt format and the first 5 hours of the new format. The station (mistakenly?) aired a half-hour music set at 11pm, starting about 6 hours into the 51-hour-long file. The station (mistakenly?) aired about a half hour of nothing but "this is the new format", starting about 22 hours into 51-hour-long file.